


Achilles and the Tortoise

by MartianSquid



Series: Zeno's Paradox [1]
Category: Sherlock (TV)
Genre: Accidental Bonding, Alpha Sherlock, Alpha/Beta/Omega Dynamics, Alpha/Omega, Alternate Universe, Alternate Universe - Canon Divergence, Bonding, Canon Divergence - The Reichenbach Fall, F/M, Knotting, M/M, Mating Bond, Mating Cycles/In Heat, Omega Jim, Omega Verse, Rough Kissing, Shameless Smut, Smut
Language: English
Status: Completed
Published: 2015-08-28
Updated: 2015-09-04
Packaged: 2018-04-17 17:42:19
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,638
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4675580
Author URL: https://archiveofourown.org/users/MartianSquid/pseuds/MartianSquid
Summary: <blockquote class="userstuff">
              <p>Jim is a secret Omega, and will never be interested in an Alpha. Which means he can't possibly feel jealous when his favorite detective shows interest in Betas.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> "In a race, the quickest runner can never overtake the slowest, since the pursuer must first reach the point whence the pursued started, so that the slower must always hold a lead."

Jim Moriarty didn’t hate his secondary gender — he just wished it were irrelevant. That four times or so out of the year, he could merely brush off the urge to mate, rather than be paralyzed by the pain of acetic resistance. He had a job to do, and it would be made nearly impossible if it were to get out what he was. 

Omegas were doing alright, rights-wise. On paper, it was illegal to discriminate based on gender, and stereotyping was generally seen as offensive. But laws did little to affect the culture, and a joke or two on the “weaker sex” usually garnered laughs. More so, despite right-to-work laws being passed over two decades ago, it was still uncommon to see an Omega with a steady job after having a child (which they were still universally expected to have at some point or another).

Besides, what did “legality” ever matter to Moriarty anyway? In the eyes of the law, he didn’t even exist. It’s not like he could lob a lawsuit if all of his clients dropped him if they found out what he was — the police would be more interested in what his clients wanted in the first place. 

Culture had a way of changing. Even today, Betas were held in higher regard in some areas — unable to be swayed by hormonal suggestion, they made better politicians, soldiers, stock brokers — anything that required a consistently level head. In a time long past, Alphas were considered the top of the hierarchy solely based on physical strength, but an age of enlightenment and rationality phased that out. A small mercy for Omegas if there ever was one, as Betas tended to be more empathetic, and not think of them as “lesser.”

Sometimes Jim thinks it’d have been preferable to be a woman, as all women were Betas, compared to the grim 10% of men. But on a non-mating day, if he weren’t around an Alpha he found attractive, Jim was just as cogent as any Beta, so it didn’t much matter. 

However, it was, on occasion, a steep caveat. The birth control favored by most tricked the body into thinking it was pregnant, and thus staved off heats for long periods of time. However, most chose to have them at least twice a year. More than six months on the suppressants lead to more unpredictable results. 

Still, it wasn’t surprising when some chose to push the envelope: the word “heat” wasn’t nearly unpleasant enough to describe how it felt. It was _hot_ , yes, his temperature would jump from a comfortable 98.6 to 100.5, but that was peanuts compared to the “body aches.” Such a clinical term. Jim would sooner equate them to being slowly ripped in half. Unavoidable unless he found himself an Alpha’s knot and soothing hormonal cocktail to coax his own down.

But that would probably mean getting bonded in a moment of desperation. Meant potentially getting pregnant (depending on if his new overlord would allow for safe birth control) and risking his life to produce children he didn’t want. 

No. He could stand two collective awful weeks a year — a wonderful trade off, really, in the face of at least 18 years of _that_. Jim was happy enough being single. In fact, he’d often thought an Alpha would _never_ make him reconsider his stance.

And then one did. 

 

* * *

 

“Reconsider” had never seemed like such an ugly word. Especially odd since it was being applied to such a beautiful specimen of a man. Of an _Alpha_.

Sherlock Holmes was no ordinary creature. He shone like a lighthouse beacon after a tumultuous journey at sea. So far away, yet just close enough at the horizon to give off hope. From his comfortable distance, Moriarty heard rumblings — that this “detective” wasn’t like the others. Saw through and destroyed his plans. What had sometimes taken _months_ for him to construct, Holmes could destroy in days.

An Alpha with a mind on him. A mind that was relentlessly cruel to _everyone_ indiscriminately, regardless of age, race or — _gasp!_ — gender. And, as a side note, seemed to rebuff all romantic and sexual advances. Interesting.

Maybe, just _maybe_ Sherlock could be different.

Jim still isn’t looking for a mate, but he sets up a test regardless. To see if the man with the prettily pointed cheekbones stood up to proper scrutiny. 

 

* * *

 

During his little game, Jim breaks his unwritten “not getting involved” rule. But Sherlock was just doing so _well_ … besides, spectating could be so _boring_. 

Still. He couldn’t just waltz in during the detective’s process. Couldn’t come as _himself_ regardless. Jim wasn’t openly an Omega, and presenting as such so early in their rivalry… it shouldn’t matter, not if Sherlock was the man he thought he was… But it did give him an idea for a disguise. 

Harkened back to his university days in the I.T. department. For a more “organic” placement in his life, Jim waits a day. Gets a coffee date in with the morgue attendant — who, by _stunning_ coincidence, was also in love with Sherlock. He wanted her for an excuse to go to the _lab_ , but the connection made it all the more justified.

He can barely sleep that night, jittery with anticipation.

Before he goes in for “work,” he sprays himself with a light mist of artificial pheromones. Generic Omega. Just enough that the renowned Sherlock Holmes, with all his keen senses, might be able to catch the faintest hint of it. A test within a test.

 

* * *

 

His surveillance texts him right around lunch. Sherlock had gone in the building. Most likely downstairs. Such excellent timing, really, and the man didn’t even know it.

Even as he made the last few steps down, he could hear Molly’s voice. _Perfect, perfect, perfect!_ To some secret embarrassment, Jim knows that his starstruck air is at least partially genuine. Nerves singing, he needs to breathe deep, give himself a moment to work up the nerve to even be in the same room…

He’d like to think that his opening of the door comes off as meek and accessible. The slightest bit of joy, fear could shine through as well. So far, he could only see the back of his head, the side as he approached. He seemed so… dignified. Stalwart. True. 

But somehow, Jim knew it was as much of a lie as he was putting on.

“So you’re Sherlock Holmes…” Jim watched his nostrils flared wide — a moment where the _beast_ lurking beneath the surface is roused. “Molly’s told me all about you. You on one of your cases?” It feels wrong, ill-fitting, to act on every instinct he’d trained himself out of years ago. To be the fluttering, doting _treat_. An object. 

“Jim works in I.T. upstairs!” Molly offered, trying to start conversation. Somewhere, she knows how important it was to him. _Kindness_. Jim saw, _If not colored by some attempt to make the great detective jealous._ “That’s how we met! Office romance!”

“Omega.”

Her face falls, “Sorry, what?” She’s already heard — Sherlock doesn’t see why she’d ask for clarification except for denial. But wasn’t it kinder just to let her know it would eventually be a dead-end? With one look, the detective could see that _Jim_ was the kind of Omega who just didn’t want to be alone. Secretly wanted an Alpha, children. _Boring_. 

“Nothing.” He shook his head lightly, trying to clear away the initial, instinctive haze of an Alpha smelling something appealing, “Hey.” It also detracts from his usual rude streak, and it won’t clear up until his “prospect” has left the room. Biology could be so _tedious_ sometimes. 

“Hey.” Jim grinned, never letting up that flirty air, only heightened by his success. _What a simple-minded lot…_ The criminal had already known this, of course, but he was somehow disappointed that the detective hadn’t completely overcome his biology. He’d wanted the full experience of being torn apart by the legend, not silently held in higher, lustful regard. 

He doesn’t get much more. _Very_ disappointing, but not entirely a strike-out. Jim, in a fit of morbid curiosity, left his number. Walking out, he figures either the sleuth will connect the dots himself, or would leave him ignored.

Jim tells himself it’ll be fine either way.

 

* * *

 

Wonderfully, Sherlock surprises him. He doesn’t take _any_ of the options Jim figured. Doesn’t connect the dots, doesn’t use his number, doesn’t _ignore_. But sends out a message that he knows _Moriarty_ will read for certain. A meeting. Without any pretenses.

Except the usual one. 

Coats and coats of blocker spray go on, a dab of antiperspirant, because _oh_ , Jim knows that with thirst this strong, and denial this long, his body is sure to sweat, his pores desperate to spit out something that would grab his intended mate’s attention. But that was too simple, and would send entirely the wrong message. No, Moriarty wanted the detective’s attention as an _equal_ , not a sex toy. 

He double, _triple_ checks with his only trusted Alpha that he smells like _nothing_. On edge after their little encounter. It wasn’t Jim’s natural smell, but he wouldn’t want to flaunt it in front of Sherlock and his little pet Alpha. If he were ever going to reveal himself (slim chance), it’d have to be in private — unfounded, but he trusted the detective not to tell anyone. 

Meeting at the pool. Where their cases first began. How sentimental. How _perfect_. So awful, really, that Jim would have to kill him someday. But, finally being realistic with himself, he couldn’t get attached. Pursuing anything _real_ with him had been a nice fantasy, but that’s all it ever could be. Jim didn’t fancy being brought down by a knot, no matter who it belonged to. 

“Although I have _loved_ this — this little game of ours.” His heartbeat sped up a moment, in the seconds before the truth, given as a lie, “Playing the fawning little Omega… did you like that bit with the underwear? _Presenting_ for you like a desperate little slut?”

He sees Sherlock’s eyes widen, recognition. That he’d been fooled by a dash of chemical suggestion — it must be so embarrassing, realizing how his senses had let him down. Oh, how disappointed he’d be to know it was happening yet again. 

 

* * *

 

Despite telling the detective to back off, Jim can’t help but continue to prod at him. 

Irene Adler, lovely, dominatrix, Beta, made her way in the world by taking Alphas down a peg. The Omega could get behind thinking like that, and it was _perfect_ for taunting his wayward interest. Most Alphas preferred Omegas, a simple matter of biology. 

But Ms. Adler just had a _way_. So Jim threw her in Sherlock’s path, not sure what outcome he was after. 

The attraction, as far as Jim can judge, is instant. That _look_ he gives her is identical to the one Sherlock had given Jim at the pool. Fire burns in his stomach, sickening, _jealousy_. _How disgusting_ , he wrinkled his nose at himself, already dangerously invested. 

Yet, the game plays itself out as Jim so ingeniously planned.

Ms. Adler lost, escaped England, but almost immediately set for execution.

However, when he thinks no one is watching, the detective slips under the radar, reappearing as a blip in Karachi. Just in time to save her. A veritable hero, saving the damsel in distress, and being thanked with sex.

Well. That wouldn’t do. 


	2. The Fall

Sherlock stood, signaling their little encounter was over. Just as well, Jim was beginning to get too warm, “Never liked riddles.” He said, voice low, coloring Jim’s cheeks some. _Much_ too warm.

Jim stood belatedly, legs shaky, but needing to be in _control_ , lest it come off as fear. “Learn to.” He whispered, throat hoarse, “Because I owe you a fall, Sherlock. I. _Owe_. You.” Forehead sweating. _Feverish_.

Oh no. _No_. He hadn’t recognized the signs until it was too late — it hadn’t happened in _so long_ … 

Biochemistry was a tricky thing. In sterile lab conditions, Omega smell could be concealed. Heats could be suppressed. Attraction could be neutralized. But such perfect scenarios rarely, if ever, happened in real life. 

Test tubes and petri dishes didn’t often encounter all three of those things, and hormones have been known to override even the strongest of scientific achievement. Rushing out double time, his pheromones were going crazy, sloughing off his shield, coming on so strong he was going into _heat_. 

Didn’t help that the Omega had opted into having them once a _year_. Unpredictable after six months, but it never seemed so pressing if he weren’t around anyone particularly appealing. On some level, he’d forgotten he was rolling the dice whenever he allowed himself congress like this. 

This far in, it was pointless to hope he could sneak out. Best chance was to let Sherlock piece it together, and hope he was just as resistant to mating as he. 

Sure as the tides, Jim watched yet again as the detective’s nostrils flared, but this time, coupled with his pupils blowing up, engulfing those cold, nearly colorless irises. The signs, and knowledge, suggested this wasn’t just biologically fueled — this was _lust_. “I’d suspected…” Sherlock’s eyes narrowed, leaning his head forward in curiosity, like this was part of some grand experiment… and Jim’s biological signals were just drab _observations_ , “But admittedly, I’d hoped it wasn’t true.”

The taller man advanced in small, languid steps. Still so carefully controlled, when any- _most_ Alphas would’ve taken it as an invitation to pounce. They weren’t even touching, but the inch or so of air between them was thick with growing arousal, Sherlock’s clear blue eyes cutting cleanly through his bones.

Jim was startled when his back hit the wall; so out of himself he hadn’t even been aware he was submitting to Sherlock’s unspoken commands. Part of him wanted to _whine_ and _beg_ for it, even if he was better than that. But as a hand rested on either side of his head, caging him in, he didn’t _feel_ like he was above it.

Pants sticking to his leg, peeling off and re-plastering with each measured breath, Jim hardly needed the reminder he was _wet_. Empty. 

“Admittedly, I was worried that it might devalue it…” Had he been talking the whole time? Jim’s body could only register the low, baritone vibrations, shaking through to his core, “But since I thought you were a Beta, it seems only incidental…”

Oh. He was making it clear. This was coupled with _intellectual desire_. 

Interesting. 

Or at least, it would be, if Jim had any wherewithal to consider it. No, all of his processing power was devoted to _what on Earth Sherlock was doing with his mouth._

Wherever that sentence ended, it began a slew of soft kisses down Jim’s neck. Little shocks with each press, building into large ones, each traveling down his spine, settling in his knees until they gave out. But Sherlock was prepared for that, catching him in those wiry-yet-sturdy arms, gathering Jim up until his legs wrapped around his waist.

Jim moaned as the tender assault kept up, vaguely feeling motion — movement? _Oh_. He sighed internally at how fuzzy his brain had become, unable to process anything that wasn’t _pleasure_. Sherlock was walking, carrying Jim over to his bedroom. The Omega reasoned that at least he wouldn’t be _caught_ like this — the headlines would read something infinitely less impressive than his botched trial if he were.

The door closed behind them, and Jim fell backward into the mattress, still connected at the waist, Sherlock towering over him, eyes hungry. Sherlock undid his legs, falling limply aside as his trousers and pants were worked off. _So little technique past kissing._ Jim noted, wondering what that could mean. It might’ve been a turn-off, his captor so eager, but his cock had already stirred, arse dripping into the sheets now, perhaps it was better not to ruin the wool. 

Still… he had to remember this for later inspection. 

Fingers. Two of them, pressing slowly into his body. It was more the _anticipation_ of the act, rather than the feeling that made Jim _yelp_ , eyes shutting hard. Then he felt them begin to _brush_ his nerves, heat radiating outward until his skin _sang_. Almost too much, but Jim couldn’t _speak_ , jaw practically wired shut. 

Pleasure was too intense, and turned into pain. But in the throes of endless hormonal conversion, pain turned back into pleasure. And somehow, he needed _more_. Suddenly, Jim was surrounded, soft skin and _muscles_ overlaying him as Sherlock had somehow instantly stripped and laid between his legs, chest-to-chest. 

Fingers kept working, coaxing breathy moans from Jim. Then they were yanked out, a _squeak_ escaping the smaller man, extending as he felt the _stretch_ of something much bigger. He squirmed, nails raking down Sherlock’s back, taking bits of his skin with him. 

Sherlock tensed, face tucking under Jim’s ear. He inhaled deeply at the base of his neck, and Jim felt _teeth_. 

 _Oh._  

Some things, even to his severely compromised brain, began to clear up.

Earlier, Sherlock was _scenting_ him. 

 _No…_ he could’ve stopped it. Maybe. If he said something. Jim wasn’t _ready_ for this, but he couldn’t say he didn’t _want_ it. 

Jim gasped as skin on his neck broke, Sherlock lapping at the blood. But the Omega began to panic: with those few seconds, all he’d ever worked toward was over. Independence was unheard of from this point on…

But then the Alpha began to move, and Jim couldn’t string together complex thoughts composed of more than one or two _words_. 

 

* * *

 

It wasn’t until it was over that the haze lifted. Gauze removed from his severely blurred vision. Scenes replayed in his head, remembering how _submissive_ he’d been. Something he’d never do if he were in his right mind. But he could only feel calm, even a tad _cheerful_ — cursed hormones, trying to tell them both they’d done something good. 

Which, physically, yes. Jim squirmed, rolled his hips minutely, gasping as a fresh jolt of pleasure spiked, knot still inflated inside him, pressing against his prostate. _Filling him up._ Such a disgusting phrase, but perfect to describe the blissful agony it brought. 

Sherlock’s arms crossed over his back, holding him. Jim stiffened, but quickly let out a breath as he let himself relax. Locked together for a few minutes, it’d only make it worse to struggle. Perhaps the detective would fall asleep, and by some miracle, the Omega would find the willpower to suffer the rest of his heat alone. 

Didn’t seem likely.

Besides, for all that went horribly wrong, Sherlock didn’t try to use any of that disgusting Alpha dirty talk. No growling about breeding or bonding him, or how eager Jim must’ve been to finally be _graced_ with a knot. No, what was interesting was how non-verbal it had been. 

Sherlock didn’t boast about claiming Jim, marking him filthy, he just _did_. He didn’t promise to fulfill him in ways he’d never been before, he just _did_. 

“Pondering the solution to entropy?” 

“Hm?” Jim languidly craned his neck up, only for Sherlock to catch his lips. “ _Mm!_ ” Wasn’t the worst line he’d ever gotten, and he pulled back slower than he should’ve. 

“Alright…” Sherlock said, taken aback, but not disappointed. He pressed his hands to Jim’s shoulders, rolling him off, the Omega wincing as his mate’s cock (even if soft now) slipped out of him. Jim stayed on his back, arse mildly sore, exacerbated by his weight, only staying still because he was too wiped out to care. 

Sherlock got off the bed on (to Jim’s silent delight) unsteady legs, shuffling to the dresser, procuring a pack of cigarettes, sticking one in his lips clumsily, turning a lighter in his hand as he lit it, “Want one?”

“Nah.” 

“Suit yourself.” He wandered over to the window, opening it and exhaling out.

“Aren’t you supposed to have quit those anyway?” Jim asked, suddenly uncomfortable with the threat of prolonged silence. 

“Had a stressful day.” Sherlock shrugged, leaning against the sill, “Got thrown in jail and everything…” 

Jim scowled, leaning his head up slightly so Sherlock could see, but the way the light hit Sherlock’s _shamelessly naked body_ gave him different ideas. His neck throbbed. _Stupid heat._ “That… was your first time, wasn’t it?” Jim’s fingers had begun prodding lightly at his tender neck wounds, as if to confirm they were _really_ there. 

“First time doing what?” He asked, releasing a cloud of smoke with slack lips, “If you want an answer, verbal or non, you must be specific in your convictions.” He turned his head slightly, smirking, “Deductions. Gathering straight-up information. That’s _my_ area.”

Jim frowned, not used to people _resisting_ interrogation. “Your first time having penetrative sex.” Then again, most interrogation was less polite, and less post-coital. 

The detective huffed a small laugh through his nose, smile tightening, “Yes.” It didn’t need to be said that it was Jim’s too. Alphas didn’t bear any marks of previous conquests — freer that way to spread their genetic material — but it was almost unheard of that an Omega didn’t. 

“But you’ve kissed before. Intensely.”

“Good, and you know that because…?”

“Showing off!” Jim announced, hiccuping slightly with the force of it, “That is also _your_ area.” He pouted out his lower lip, “ _I_ don’t need to justify how I know things in order to get my rocks off.”

“No.” _That stupid, smug grin._ “You have me for that.”

Jim actively _wanted_ to be angry. To stand up and slap that expression off his face. To walk out and prove him wrong. But right now he just found it _cute_. _Damn evolution._ “When _this_ is over…” He gestured over his body, already beginning to heat up again, “You’re going to pay for that.”

“God, I hope so.”

 


End file.
